Meal Replacements Don't Help Obese Teens

Dietetic shakes and prepackaged entrees help obese teenagers lose weight loss at first. But "meal replacements" were no better than a standard low-calorie diet for helping young people continue losing weight over the course of a year....

Dr. Robert L. Berkowitz, Children's Hospital of Philadelphia, and his team note in their report that swapping regular meals for shakes, bars or prepackaged entrees can be a useful weight loss strategy for adults.

One reason that these meal replacements may work is that they take the guesswork out of dieting; people often sharply underestimate their calorie intake when they eat regular foods. Given that adolescents also underestimate how many calories they consume, the researchers sought to investigate whether meal replacements might be helpful for them, too.

The researchers randomly assigned 113 obese teens and their families to one of three regimens for a year: (1) a standard 1,300- to 1,500-calorie-a-day diet; (2) four months of meal replacements (three SlimFast shakes, one prepackaged entrée, and five servings of fruits and vegetables per day) followed by eight months on the conventional diet; or (3) an entire year of meal replacements.

At four months, patients in the meal replacement groups had reduced their body mass index (BMI) by a mean of 6.3%, compared to 3.8% for teens in the low-calorie diet group.

But by the end of the year, there was no significant difference in mean BMI reduction between the three groups: 2.8% for the low-calorie diet group, 3.9% with four months of meal replacements, and 3.4% with a year of meal replacements.

One-third of the patients dropped out of the study. Among those who stuck with it, adherence waned as time wore on. By the end of 12 months, the researchers note, the meal-replacement group reported using SlimFast only 1.6 days a week, compared with 5.6 days a week in month two.

"The potential benefit of (meal replacement) in maintaining weight loss was not supported," the researchers conclude, and further study is needed to find ways of getting obese teens to start diets and stay on them.

Teens with Type 2 Diabetes Have Brain Abnormalities

Obese adolescents with Type 2 diabetes have diminished cognitive performance and subtle abnormalities in the brain, researchers at NYU Langone Medical Center found…

Antonio Convit, MD, professor of Psychiatry and Medicine at NYU Langone Medical Center and the Nathan S. Kline Institute for Psychiatric Research, NY, explained that, "This is the first study that shows that children with Type 2 diabetes have more cognitive dysfunction and brain abnormalities than equally obese children who did not yet have marked metabolic dysregulation from their obesity."

"The findings are significant because they indicate that insulin resistance from obesity is lowering children's cognitive performance, which may be affecting their ability to perform well in school."

Researchers studied 18 obese adolescents with Type 2 diabetes and compared them to equally obese adolescents from the same socio-economic and ethnic background but without evidence of marked insulin resistance or pre-diabetes.

Investigators found that adolescents with Type 2 diabetes not only had significant reductions in performance on tests that measure overall intellectual functioning, memory, and spelling, which could affect their school performance, but also had clear abnormalities in the integrity of the white matter in their brains.

"Now we see that subtle changes in white matter of the brain in adolescents may be a result of the abnormal physiology that accompanies Type 2 diabetes. If we can improve insulin sensitivity and help children through exercise and weight loss , perhaps we can reverse these deficits."